Shibboleth
A shibboleth ( SHIB-əl-eth, -ith; Hebrew: שבלת [ʃiˈbolet]) is any custom or tradition—usually a choice of phrasing or single word—that distinguishes one group of people from another. Historically, shibboleths have been used as passwords, ways of self-identification, signals of loyalty and affinity, ways of maintaining traditional segregation, or protection from threats.